CLK270cdi - how much smoke is too much?

[Alex Crow]

your cars should not have noticable smoke guys! yes egr valves are possible causes, mainly on 320 cdi2 engines, but most common by far is leaking intake tract losing pressure after maf. ecu injects fuel according to maf values (as well as other inputs) but the pressure, and so volume, is lower than metered so you get overfuelling black smoke. injector sealing problems will not cause black smoke, nor will DPFs.

that scenario. would love to tell you which bit to change, but sadly it is not going to be that easy. black smoke on cdis is almost always attributed to a loss of boost (turbo) pressure.

 

[oigle]

jibcl500 - to be fair mine emits only a small puff on acceleration out of roundabouts etc. However, I am somewhat disappointed that even this should occur!

I wouldn't be disappointed. My ML, when new, exhibited almost no smoke on initial acceleration but its throttle response was horrible, dangerous in fact. I had the ecu remapped and now it gives a good puff of smoke when the throttle is stabbed and the motor responds immediately - no lag. Much rather have that. I also notice that before and after the remap, I would get a noticeable plume of black when working very hard up a long hill at around 3000rpm with the caravan on the back. The longer the hill went, the worse it got, to a point. No issues with normal driving and no apparent poor economy.